Image printer

Abstract: An image printer includes a projection-exposure section for projecting an image born on a film onto a photosensitive material, an image-exposure section for exposing the photosensitive material based on image information comprised of a plurality of image areas each including color data relating to a plurality of colors, and a transport unit for transporting the photosensitive material through the projection-exposure section and the image-exposure section. The image-exposure section includes a plurality of exposure units for dividing the image information into a plurality of lines and exposing the photosensitive material with switching exposing colors corresponding to the plurality of color data, a moving device for moving the plurality of exposure units and the photosensitive material relative to each other in a direction perpendicular to the lines, and a moving-exposure control unit for controlling operations of the exposure units and the moving device. The exposure control unit is capable of effecting a moving exposure control in which the plurality of exposure units respectively effect exposure operations thereof in a parallel manner.

Description: BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to an image printer, and more particularly to an image printer including a projection-exposure section for projecting an image born on a film onto a photosensitive material, an image exposure section for exposing the photosensitive material based on image information comprised of a plurality of image areas each including color date relating to a plurality of colors, and transport means for transporting the photosensitive material through the projection-exposure section and the image-exposure section. 2. DESCRIPTION OF THE RELATED ART Such image printer as described above may be used for a variety of purposes. For instance, the printer allows the projection-exposure section and the image-exposure section to be utilized independently of each other. The printer is also usable for a multiple exposure operation. In this case, the projection-exposure section effects an exposure of the film image onto a certain portion of the photosensitive material and also the image-projection section effects a further overlapping exposure of another image onto the same portion of the photosensitive material while the photosensitive material is being transported by the transport means through the projection-exposure section and the image-exposure section. Conventionally, the image-exposure section of the above-described image printer effects an exposure of a video image displayed on a CRT monitor onto the photosensitive material, the video image being comprised of a plurality of image areas each including color data relating to a plurality of colors. Document US 4,878,111 discloses an image apparatus which projects a transparent image onto a photomaterial. This apparatus comprises a CRT and a screen image produced by said CRT is reproduced on the photomaterial. The CRT is controlled by image measuring means reading image data and a computer unit for the purpose of color and contrast correction by means of the CRT. Document EP 0 615 378 A1 (prio. date: 12/03/93, publ date: 14/09/94) which was published after the priority date of this application shows an image printer including a protection-exposure section for protecting a film image onto a photosensitive material, an image exposure section for exposing the photosensitive material based on image information and a reader device for reading the image information of the film image which the image information being devided into a plurality of areas. The image exposure section comprises a projection unit, an optical path connected to the projection unit, a light-modulating filter and an exposing-color control shutter. The photosensitive material is exposed in succession at the image exposure section with a one line amount of image information while switching over different exposing colors. Document FR 2 576 118 relates to the art of forming edges in an image recording area of print, more particularly, forming square edges on the print. For this purpose, light is transmitted from a color head via a fiber to a tunnel section so as to expose the edges. Furthermore, a connector is provided for changing the color of the edges. According to the above conventional art, however, the image-exposure section including the CRT monitor tends to be large and complicated, such that it has been difficult to form the entire printer apparatus simple and compact. Thus, there remains room for improvement in this respect. The present invention attends to the above-described state of the art. And, a primary object of the present invention is to provide an improved image printer which is compact and simple and which is superior in processing capacity through minimization of undesirable reduction in the speed of the image exposure operation. SUMMARY OF THE INVENTION For accomplishing the above-noted object, an image printer according to the present invention comprises an image printer as defined in claim 1. In the case of the above-described construction, the projection means includes a plurality of projection units for projecting a plurality of exposing colors and a plurality of exposure-color control shutters for independently and selectively opening/closing a plurality of optical paths for guiding the light from the respective projection units to a plurality of exposure heads. Then, through the independent and selective opening/closing of the exposure-color control shutters, the light beams of the plurality of exposing colors projected from the projection units are guided respectively to the exposure means. In a preferred embodiment, the light beam guided to the exposure means is divided into a plurality of areas by the plurality of exposure-control shutters provided inside the exposure means and then guided to the photosensitive material. Accordingly, the light beams of the exposing colors formed independently of each other may be guided in the independent manner to the same exposure-control shutter by controlling the opening/closing of the exposure-color control shutters. As a result, since the light beams of the exposing colors formed independently of each other through the control of opening/closing of the exposure-color control shutters may be guided to the same exposure-control shutters, the same area may be exposed with each exposing color. This can avoid deterioration in the image quality due to erroneous displacement of the colors. Further, since the projections of the light beams of the respective exposing colors are controlled by means of the exposure-color control shutters, the construction of the projection means for projecting with switching over the exposing colors may be simple, and it becomes also possible to reduce the swichover time period of the exposing colors. The above-described exposing-color control shutters are preferably electronic shutters. With this, the light beams of the plurality of exposing colors projected from the plurality of projection units are guided to the exoposure means with the light beams being selected according to their colors by the electronic shutters acting as the exposure-color control shutters. Thus, the exposing colors may be switched over through the control of these electronic shutters. In comparison with mechanical shutters, the electronic shutters are advantageous for less operation noise, easier control and also for reduced time period of exposure color switchover. The optical paths for guiding the light beams from the plurality of projection units to the exposure means comprise optical fibers so that the plurality of projection units may be disposed distantly from the exposure means. With such distant arrangement of the projection units from the exposure means, it becomes possible to avoid variation in the sensitivity of the photosensitive material due to generation of heat from the projection units. According to a still further aspect of the invention, a diffusing member for diffusing the light beam projected from the optical fiber is provided on the side of the optical fiber relative to the plurality of exposure-color control shutters. With the above-described construction, the diffusing member for diffusing the light beam is disposed closer to the optical fiber than to the plurality of exposure-color control shutters. Then, the light beams of the plurality of exposing colors may be uniformly diffused by the diffusing member to be guided to the exposure-control shutters. As a result, because of the uniform diffusion of the light beams of the plurality of exposing colors projected from the plurality of projection units and the subsequent guiding of the same to the exposure-control shutters, it is possible to render further uniform the light beam to be guided to the exposure-control shutters, thereby to achieve further improvement in the image quality. Further and other objects, features and effects of the invention will become apparent from the following more detailed description of the embodiments of the invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic construction view of an image printer according to a still further embodiment of the present invention, Fig. 2 is a perspective view of the image printer of Fig. 1, Fig. 3 is a view showing constructions of a projection means and exposure head of Fig. 1, Fig. 4 is a flow chart relating to the embodiment of Fig. 1, Fig. 5 is a view showing connection between an optical fiber and an exposure head of Fig. 1, and Fig. 6 is a view showing connection between an optical fiber and an exposure head relating to a still further embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an image printer relating to the present invention will be detailed next with reference to the accompanying drawings. In the embodiment of the invention, as shown in Figs. 1 and 2, the image printer 1 includes a projection-exposure section P for projecting/exposing image information of a film 2 onto the print paper 3 as the photosensitive material, on image-exposure section G for dividing into lines image information to be exposed onto the print paper 3 and exposing each line onto the same, a loop forming unit R for forming a loop of the print paper 3 in order to effect the transport of the print paper 3 at the projection-exposure section P and that at the image-exposure section G independently of each other, the developing section D for developing the print paper 3 having been exposed at either the projection-exposure section P or the image-exposure section G, and a control unit C for controlling the above-described components of this image printer 1. The control unit C is connected to an input device I for inputting the image information and also to a control panel O for effecting a variety of mode setting operations and instruction inputting operations. The print paper 3 having been withdrawn from a print-paper holder 4 in which the print paper 3 is accommodated in the rolled state is exposed at either one or both of the projection-exposure section P and the image-exposure section G; then, this print paper 3 is developed through a developing section D to be discharged therefrom, with the print paper 3 being cut into a paper piece containing one-frame amount of image information. The image printer 1 provides two modes of a projection-exposure mode and an image-exposure mode. In the projection-exposure mode, the image of the film 2 is exposed onto the print paper 3 only at the projection-exposure section P. In the image-exposure mode, the print paper 3 is exposed at the image-exposure section alone. The selection of one of these two modes to be executed is done by inputting an instruction from the control panel O. Further, the image composing exposure utilising both of these two modes is possible. Through the instruction input from the control panel O, it is selected which image information is to be exposed in the image-exposure mode, i.e. selection between the image information inputted by the input device I and the image information of the film 2 read in a manner to be described later, or selection of composite image using both of the two kinds of image information. The projection-exposure section P includes a projection-exposure light source 10, a light-modulating filter 11 for adjusting color balance of light to be irradiated onto the film 2, a mirror tunnel 12 for uniformly mixing light color components having passed through the light-modulating filter 11, a printing lens 13 for printing an image on the film 2 onto the print paper 3, and the shutter 14, with all these components being aligned along a common optical axis. On the upstream side in the film transport path of the film 2 at the projection-exposure section P, there is provided an image sensor 15 acting as a reader means for reading the image information of the film 2 with the image information being divided into a great number of areas. This image sensor 15 is operable to irradiate white light onto the film 2 and measuring, by e.g. a CCD line sensor, intensity of its reflected or transmission light, with the light being decomposed into three primary colors of red, green and blue. Then, the image information read by the image sensor 15 is utilized for both the exposure at the projection-exposure section P and the exposure at the image-exposure section L. At the projection-exposure section P, based on the image information of the film 2 read by the image sensor 15, the control unit C controls the light-modulating filter 11 to adjust the irradiating light of the projection-exposure light source 10 to a color balance according to the color densities of the image of the film 2, so that this adjusted light is irradiated onto the film 2 to print the image of the film 2 onto the print paper 3. The loop forming unit R includes the rollers 20, 21 for transporting the print paper 3 and the motor M1 for rotatably driving the roller 20. Between the roller 20 on the upstream side of the transport direction of the print paper and the roller 21 on the downstream side of the transport direction of the print paper, though not shown, there is disposed a flap switchable between a condition for guiding the print paper 3 between the rollers 20, 21 in a straight manner and a further condition for allowing the print paper 3 to be formed into a loop. Then, with formation of the loop, it is possible to set a transport speed of the print paper 3 at the projection-exposure section P and a transport speed of the same at the image-exposure section G, independently of each other. As shown in Figs. 1 and 3, projection means RE is comprised of three projection units F for respectively projecting the three primary colors, an optical fiber bundle 46 for respectively guiding the light beams from the projection units F to the exposure head 34, and of three exposure-color control shutters 33r, 33g, 33b for opening/closing the optical paths to the optical fiber bundle 46 according to the colors. Incidentally, the three projection units F include three light sources 31r, 31g, 31b and red, green and blue color filters 32r, 32g, 32b. In operation, as the light beams projected from the light sources 31 pass the color filters of the respective colors, three kinds of exposing colors (red, green, blue) are produced. The exposure head 34 includes a diffusing member 47 for diffusing the light projected from the optical fiber bundle 46, a plurality of exposure-control shutters 30S for opening/closing the light from this diffusing member 47 with the light being divided into a plurality of areas, and a SELFOC (registered trade mark of Nippon Sheet Glass Co., Ltd. ) lens alley 34c for converging the respective light beam components opened/closed through the exposure-control shutters 30S on the print paper 3. The exposure-control shutters 30S and the SELFOC lens alley 34c are linearly disposed in the direction perpendicular to the transport direction of the print paper 3. Accordingly, the plurality of exposure-control-shutters 30S are operable to control the exposure of the print paper 3 with the light beams from the projection means RE with the light being divided into a plurality of areas. Incidentally, the light beams of the respective colors (red 46r, green 46g, blue 46b) guided by the optical fiber bundle 46 are projected to the exposure head 34 according to an order illustrated in Fig. 11. Each of the exposure-control shutters 33r, 33g, 33b and of the exposure-control shutters 30S, though not shown, is comprised of PLZT element interposed between a polarizer and an analyzer. Then, by varying the voltage to be impressed between a pair of electrodes attached to each PLZT element, the polarizing direction of the light passing between the electrodes is varied so that the PLZT element allows or inhibits passage of the light therethrough. In this way, these shutters function as electronic shutters. Accordingly, as the voltages to be impressed to the respective PLZT elements of the three exposure-color control shutters 33r, 33g, 33b to switch over the exposing color to one of the three primary colors of red, green and blue and also the voltages to be impressed to the PLZT elements of the exposure-control shutters 30S, exposure of one-line amount of the image information divided into a plurality of areas is effected for each area by an exposure amount corresponding to its exposing color. That is to say, while the exposure head 34 is exposing the one-line amount of the image information, the exposure-color control shutters 33r, 33g, 33b are opened and closed one time in series, thereby to exposure all of the three primary colors. The exposure-control shutters 30S are adapted to be opened and closed in synchronism with the exposure-color control shutters 33r, 33g, 33b. For instance, when the projection means RE projects a blue light beam, the opening time period (exposure time period) of each of the exposure-control shutters 30S is varied depending on the density of the blue component to be exposed of each area. That is, the higher the density, the longer time period the shutter is opened. On the downstream side of the print paper transport passage at the image-exposure section G, there are provided the roller 22 for transporting the print paper 3 and the motor M2 for driving this roller 22. Then, the roller 22, the motor M2 together with the roller 20 and the motor M1 constitute the transport means H. Under the control of the control unit C, at the image-exposure section G, as the one-line amount of image information is exposed in series onto the print paper 3 with switching over the exposing color, the roller 22 is driven by the motor M2 to transpert the print paper 3 by a distance corresponding to the one-line amount. Then, as these operations are repeated with shifting the image information by one line amount at each time, the print paper 3 is exposed with the entire one-frame amount of the image information. The developing section D, though not shown, includes the plurality of tanks filled with processing liquids for developing the exposed print paper 3, so that the print paper 3 may be developed through its successive passage through the plurality of tanks. The input device I comprises an image scanner for scanning and reading various kinds of image information with the information being divided into a plurality of areas. Then, the read information is converted into density information of the three primary colors of red, green and blue and then transmitted to the control unit C. The control unit C includes a memory 35 for storing the program for controlling the respective components, and various kinds of image information such as the image information inputted form the input device I and the image information read by the image sensor 15. Next, the control scheme effected by the control unit for controlling the operations of the respective components will be described with reference to the flow chart of Fig. 4. First, the image sensor 15 reads the image information of the film 2 introduced into the projection-exposure section P as color density information of the three primary colors of red, green and blue (step #1). In this, if the film 2 comprises a negative film, the read density information concerning the three primary color components need to be converted into density information of complementary colors of the respective color components. Then, it is judged whether the operation mode of the image printer 1 is presently set to the image-exposure mode or the projection-exposure mode (step #2). If the mode is set to the projection-exposure mode, by utilizing the image information obtained at step #1, the light-modulating filter 11 is controlled to be adjusted for the optimal color balance (step #3). Thereafter, by utilizing the image information of step #1, the exposure time period is calculated (step #4). Then, based on the result of calculation of the exposure time period, the shutter 14 is activated to expose the print paper 3 (step #5). On the other hand, if it is judged at step #2 that the operation mode is presently set to the image-exposure mode, the exposure time periods for the respective color components of the respective areas are calculated (step #6). Then, based on the results of these calculations, the exposure-color control shutters 33r, 33g, 33b and the exposure-control shutters 30S are controlled to effect an image exposure (step #7). This image exposure under the controls of the exposure-color control shutters 33r, 33g, 33b and the exposure-control shutters 30S is effected for each of the three primary color components of red (r), green (g) and blue (b) (step #8), thereby to complete the image exposure of one-line amount of the image information. Incidentally, though not described in the flow chart, an image exposure of one-frame amount of the image information is completed after the above-described one-line image exposure operation is effected for a predetermined number of lines. By utilizing both of the projection-exposure mode and the image-exposure mode, a composite image may be exposed at the image-exposure section G by e.g. double-exposing the image or character data inputted by the input device I on the portion of the print paper having been exposed by the projection-exposure of the film image. (1) In the foregoing embodiment, the light beams of three colors (red 46r, green 46g, blue 46b) are used for the exposure. The colors are not limited to these kinds; for instance, a light beam of any other color may be used for the exposure. It is also conceivable to add a further exposure means of any other color of e.g. orange. (2) In the foregoing embodiment, the light beams of the respective colors (red, green, blue) guided by the optical fiber bundle 46 are projected to the exposure head 34 in the order illustrated in Fig. 5. Instead, these beams may be projected to the exposure head 34 according to a further order illustrated in Fig. 6. That is, what is essential here is that the optical fiber bundle 46 and the exposure head 34 are so connected to each other to allow the light beams projected from the optical fiber bundle 46 to be uniformly diffused by the diffusing member 47. The arrangement that each of the three optical fibers for guiding the three light beams of three colors corresponds to each of the exposure-control shutters 30S is not absolutely necessary. (3) In the foregoing embodiment, the exposure-color control shutters 33r, 33g, 33b and the exposure-control shutters 30S comprise the electronic shutters using PLZT elements. Instead, mechanical shutters as employed in a photographic camera may be used. (4) In the foregoing embodiment, at the image-exposure section G, the light beams from the respective projection units F are guided to the exposure head 34 by means of the optical fiber bundle 46. Alternatively, the light beams from the projection units F may be directly converged onto the exposure head by means of lenses. Further, the light beams from the projection units F may be converged by e.g. lenses and then this converged light may be guided to the exposure head 34 by means of the optical fiber bundle 46. In this case, the diffusing member 47 provided inside the exposure head 34 may be eliminated. (5) In the foregoing embodiment, when the print paper 3 is exposed at the image exposure section G, the one-line amount exposure operation and the line- line amount of transporting operation of the print paper 3 are repeated in the alternate manner, thereby to expose the each line of the image information. Instead, a further arrangement is conceivable in which the exposure operations of the respective lines of the image information are effected one after another while the print paper 3 is being transported in a continuous manner at a predetermined speed. (6) In the foregoing embodiment, during the one-line exposure by the exposure head 34, the exposure-color control shutters 33r, 33g, 33b are opened and closed for one time respectively in series, thereby to expose all of the three primary colors. Yet, in case the exposure time periods of the respective colors are the same through the entire areas, i.e. in case the densities of the respective colors are constant through the entire areas, the exposure-color control shutters 33r, 33g, 33b of the respective colors may be opened and closed at the same time, thereby to expose all the colors at one time. (7) In the foregoing embodiment, the respective exposure-control shutters 30S are adapted to vary their opening time periods (i.e. exposure time periods) depending on the densities to be exposed for each area. Instead, the exposure time periods may be varied by changing the number of times of opening of the same. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims: An image printer having: a projection-exposure section (P) for projecting an image born on a film (2) onto a photosensitive material (3); reading means (15) for reading image information on the film (2), the image information being comprised of a plurality of image areas each including color data relating to a plurality of colors; an image-exposure section (G) for exposing the photosensitive material (3) based on the image information, transport means (H) for transporting the photosensitive material (3) through the projection-exposure section (P) and the image-exposure section (G); characterized in that the image-exposure section (G) comprises: a single exposure means (34) for dividing said photosensitive material (3) into a plurality of adjacent parallel lines and exposing in sequence one line after the other on said photosensitive material (3) based on said color data for each line of said photosensitive material (3); projection means (RE) for projecting light onto the photosensitive material (3) and switching over a plurality of exposing colors, the projection means (RE) including: a plurality of projection units (F); each projection unit (F) projecting an exposing color different from an exposing color of other projection units; a plurality of optical paths formed by a plurality of respective optical fibers (46), each path corresponding to one of said projection units and guiding the light of this projection unit to said single exposure means (34); and a plurality of exposing-color control shutters (33r, 33g, 33b) each interposed between a respective projection unit and the ends of the corresponding optical fibres for independently and selectively opening/closing said plurality of optical paths. An image printer as defined in Claim 1, characterized in that said exposing-color control shutters (33r, 33g, 33b) are electronic shutters. An image printer as defined in Claim 1, characterized in that a diffusing member (47) for diffusing the light beam projected from the optical fibers (46) is provided on the side of the optical fiber (46) opposite to the side corresponding to the plurality of exposure-color control shutters (33r, 33g, 33b). An image printer as defined in claim 3, characterized in that said single exposure means (34) include a plurality of exposure-control shutters (30S) for opening/closing the light from the diffusing member (47) so as to divide the light into a plurality of areas, and a SELFOC (registered trade mark of Nippon Sheet Glass Co., Ltd.) lens alley (34c) for converging the respective light beam components opened/closed through the exposure control shutters (30S) on said photosensitive material (3).

Inventors: TANIBATA TOHRU, TANIBATA, TOHRU, TANIBATA, TOHRU, C/O NORITSU KOKI CO., LTD.
Applicants: NORITSU KOKI CO LTD, NORITSU KOKI CO., LTD.
Application year: 1994
Main classification: G03B27
IPC codes: G03B27, H04N1